CSWIP 3.1 Welding Multiple Choice Exam Quiz!

A Hydrogen controlled MMA electrode can always be recognized by the EN code letter (or AWS code number). The EN code letter or AWS code number indicates the specific type and characteristics of the electrode, including the level of hydrogen control. This information is crucial in selecting the appropriate electrode for a particular welding application, as hydrogen control is important in preventing hydrogen-induced cracking and ensuring the quality of the weld. The electrode length, trade name, and color of the covering may vary among different manufacturers and types of electrodes, but the EN code letter or AWS code number remains consistent as a reliable identifier.

Using MMA electrodes with the flux covering removed as filler rods for TIG welding should not be allowed because the weld metal composition may be wrong. MMA electrodes are designed specifically for shielded metal arc welding (SMAW), where the flux covering plays a crucial role in providing protection and controlling the composition of the weld metal. Removing the flux covering can lead to improper alloying elements and impurities in the weld, resulting in weak or defective welds. Therefore, it is important to use filler rods specifically designed for TIG welding to ensure the correct weld metal composition.

The correct answer is Basic, cellulosic and rutile. These are the three main types of MMA (Manual Metal Arc) electrodes used for welding C (carbon) and C-Mn (carbon-manganese) steels. Basic electrodes are designed for welding high-strength steels and provide excellent mechanical properties. Cellulosic electrodes are used for all-position welding and provide deep penetration and good arc stability. Rutile electrodes are versatile and suitable for a wide range of applications, offering good welding performance and easy slag removal.

During TIG welding, purging the pipe bores with argon helps to prevent oxidation of the root bead. When the pipe bores are purged with argon, it creates an inert atmosphere that displaces oxygen. This is important because oxygen can react with the hot metal, leading to oxidation and the formation of unwanted oxides. By preventing oxidation of the root bead, the quality of the weld is improved, ensuring a strong and durable joint.

Arc blow is the deflection of the arc by magnetic forces that can make welding difficult to control. When welding, magnetic fields can be created due to the flow of current, and these magnetic fields can cause the arc to deviate from its intended path. This can lead to erratic and unstable welding, making it challenging for the welder to maintain control over the process. Therefore, the term "arc blow" is commonly used to describe this phenomenon.

The term "low hydrogen electrode" refers to a type of electrode that is designed to minimize the amount of hydrogen that is produced during the welding process. These electrodes typically have a basic covering, which means that they contain a high concentration of basic compounds, such as calcium carbonate or calcium fluoride. The basic covering helps to neutralize any hydrogen that is produced, preventing it from causing defects in the weld. This type of electrode is commonly used for welding high-strength steels and other materials that are susceptible to hydrogen-induced cracking.

A qualified Welding Procedure Specification serves multiple purposes. It provides instructions to the welder, guiding them on how to perform the welding process correctly. It also gives important information to the welder, such as the materials to be used, welding parameters, and any special considerations. Additionally, a qualified Welding Procedure Specification instills confidence that the resulting welds will possess the specified properties, ensuring that they meet the required quality standards. Therefore, all of the given options are correct.

The number 141 refers to the welding process when it is written next to the tail when using symbols. This number is used to specify the specific welding process that should be used for a particular application. Each welding process is assigned a unique number, and the number 141 corresponds to a specific welding process.

When welding travel speed is doubled but the current and voltage remain the same, the heat input is reduced by 50%. This is because heat input is directly proportional to the welding travel speed. When the travel speed is doubled, the time the heat is applied to the material is halved, resulting in a 50% reduction in heat input.

Excessive current is the most likely cause of weld spatter during MMA welding. When the current is too high, it leads to an excessive amount of molten metal being produced, which can result in spatter. The excessive heat generated by the high current causes the molten metal to splatter and scatter around the weld area, creating spatter. This can negatively affect the quality and appearance of the weld, as well as increase the risk of weld defects. Therefore, it is important to ensure that the current used during MMA welding is properly controlled to prevent excessive spatter.

A typical temperature range for baking basic coated electrodes is 300-350°C. This temperature range is necessary to remove any moisture or contaminants from the electrode's coating, ensuring optimal performance during welding. Baking at lower temperatures may not effectively remove all moisture, leading to poor weld quality. On the other hand, baking at higher temperatures can cause the coating to deteriorate, reducing the electrode's effectiveness. Therefore, the recommended temperature range of 300-350°C strikes a balance between moisture removal and maintaining the integrity of the electrode's coating.

Cellulosic electrodes are used for stovepipe welding in overland pipeline construction. Cellulosic electrodes have a high cellulose content in their coating, which produces a thick and easily removable slag. This slag helps to protect the weld pool from atmospheric contamination and provides excellent penetration. Cellulosic electrodes also have a deep, narrow arc that allows for better control and maneuverability during welding. They are commonly used for pipeline welding due to their ability to produce strong and reliable welds in various positions and conditions.

A current slope-out device in TIG welding helps reduce the risk of crater cracking. Crater cracking is a common issue in TIG welding where cracks form at the end of a weld due to the rapid cooling of the molten metal. By gradually reducing the welding current at the end of the weld using a current slope-out device, the cooling process is slowed down, allowing the metal to solidify more evenly and reducing the risk of cracks forming.

The unit KJ/mm is used to express heat input. Joules is a unit of energy, N/mm2 and J/mm2 are units of pressure, and KJ/mm is a unit of heat input. Heat input refers to the amount of heat energy transferred into a system or material.

The steel with 18% Cr and 8% Ni is considered non-magnetic because it contains a high amount of nickel, which has a strong effect on reducing the magnetic properties of the steel. Nickel is a non-magnetic material, and when added to steel in significant amounts, it can create a non-magnetic alloy. Therefore, the presence of 18% Cr and 8% Ni in the steel composition makes it non-magnetic.

In MMA (Manual Metal Arc) welding, the penetration of the weld is mainly controlled by the current. The higher the current, the greater the heat generated, leading to deeper penetration. The current determines the amount of energy transferred to the electrode, which in turn affects the melting and fusion of the base metal. Therefore, adjusting the current is crucial in achieving the desired depth and quality of penetration in MMA welding.

Molybdenum is added to steel to provide resistance to creep at elevated service temperatures. Creep is the gradual deformation of a material under constant stress at high temperatures. Molybdenum enhances the high-temperature strength and stability of steel, making it more resistant to deformation and ensuring its structural integrity in demanding conditions. Nickel, manganese, and aluminum may have other beneficial effects on steel properties, but they do not specifically contribute to resistance against creep at elevated temperatures.

An arc strike on a steel component is considered unacceptable because it may cause hard spots and cracking. Hard spots occur when the heat from the arc strike causes localized hardening of the steel, leading to reduced ductility and potential failure under stress. Cracking can also result from the intense heat of the arc strike, causing the steel to become brittle and susceptible to fractures. Therefore, both these outcomes make arc strikes undesirable and against the codes.

Silicon is added to steel and the covering of MMA electrodes to provide deoxidation. Deoxidation is the process of removing oxygen from the steel, which helps improve the overall quality and properties of the steel. By adding silicon, it reacts with the oxygen present in the steel and forms silicon dioxide, which is a stable compound. This helps prevent the formation of undesirable oxides in the steel, ensuring a cleaner and more homogeneous material.

Constant current is the type of power source characteristic that is normally used for manual welding. In manual welding, the current needs to remain constant throughout the process to ensure consistent and controlled heat input. Constant current power sources provide a stable and steady current output, allowing the welder to have better control over the welding process. This characteristic is preferred for manual welding as it helps in achieving desired weld quality and prevents overheating or distortion of the workpiece.

Exceeding the maximum width for individual weld beads may result in a reduction in heat-affected zone (HAZ) toughness. The HAZ is the area surrounding the weld where the base metal's microstructure is altered due to the heat of welding. If the weld bead width is too large, it can lead to excessive heat input and slower cooling rates in the HAZ. This can cause the formation of coarse grains and potentially reduce the toughness of the HAZ, making it more susceptible to cracking or brittle fracture.

The Nick break and fillet fracture tests are used for assessing weld quality. These tests help determine the strength and integrity of a weld by examining the presence of any cracks or fractures. By conducting these tests, one can evaluate the overall quality of the weld and ensure that it meets the required standards.

In a transverse tensile test, brittleness is indicated when the fracture surface is flat and featureless but has a rough surface. This suggests that the material failed abruptly and without significant plastic deformation. The absence of any reduction in cross-section or beach marks indicates that the fracture occurred in a brittle manner, with minimal energy absorption or deformation before failure.

The correct answer is DC negative. TIG welding, also known as Gas Tungsten Arc Welding (GTAW), is a process used for welding various materials. DC negative polarity means that the electrode (tungsten) is connected to the negative terminal of the power source, while the workpiece is connected to the positive terminal. This configuration provides better control over the welding process, as it allows for deeper penetration and improved stability of the arc. However, when welding aluminum and magnesium, AC or square wave AC polarity is used to prevent overheating and ensure better arc stability.

A fusible insert for TIG welding helps in giving controlled root penetration. This means that it allows for precise control over the depth and penetration of the weld at the root. This is important because it ensures that the weld is strong and secure, as well as preventing any potential defects such as lack of fusion or incomplete penetration. By providing this controlled root penetration, the fusible insert helps to achieve a high-quality weld with optimal strength and integrity.

The chemical composition of the weld metal deposited by a C-Mn steel MMA electrode is usually controlled by additions in the flux coating. The flux coating contains various elements and compounds that are added to the electrode to influence the composition of the weld metal. These additions can include alloying elements, deoxidizers, and stabilizers, among others. The flux coating melts during the welding process and reacts with the base metal, resulting in a weld metal with a desired chemical composition and properties. The core wire composition, iron powder in the flux coating, and dilution from the base material can also have some influence on the weld metal composition, but it is primarily the additions in the flux coating that control it.

The correct answer is E 38 3 R. According to the question, the electrode type that is classified as BS EN 499 is E 38 3 R.

The surface of a fatigue crack is smooth because the crack propagates through the material in a progressive manner, causing minimal deformation and tearing of the surrounding material. As the crack grows, it creates a smooth fracture surface without any significant roughness or tearing. This smooth surface is a characteristic feature of fatigue cracks and distinguishes them from other types of fractures that may exhibit rough and torn surfaces.

In AWS 2.4, a weld symbol for the other side is placed above the solid line. This indicates that the welding is to be done on the side that is opposite to the side shown in the drawing. Placing the symbol above the solid line helps to clearly indicate the location and direction of the weld on the other side of the joint.